Supercritically Extracted Mealworm Oil Alleviates High-Fat Diet-Induced Obesity by Modulating Gut Microbiota in Mice

In this study, we investigated the effects of mealworm oil (MO) supplementation on gut microbiota composition and lipid metabolism in male C57BL/6 mice with high-fat diet (HFD)-induced obesity. The mice were divided into five groups: normal diet (NC), high-fat diet (HFD), HFD with low MO (MOL), HFD with high MO (MOH), and HFD with olive oil (PC). After 16 weeks, body fat composition was analyzed using dual-energy x-ray absorptiometry. MOH intake reduced fat mass and abdominal circumference. MO supplementation decreased body weight, fat mass, and serum lipid levels, and improved insulin resistance. Importantly, MANCOVA/ANCOVA analyses indicated that these metabolic improvements were not solely attributable to reduced food intake. Gut microbiota analysis was performed using 16S rRNA sequencing. Firmicutes were predominantly enriched in the HFD group, while Verrucomicrobiota were enriched in the MOH group. Firmicutes and Deferribacterota showed positive correlations with lipid content and related indicators, whereas Bacteroidetes and Verrucomicrobiota displayed negative correlations. As a result of these changes in microbiota composition, lipogenesis-related genes and proteins were downregulated in the MOH group compared to the HFD group. These findings suggest that MO alleviates obesity in HFD-fed mice by modulating gut microbiota composition and the lipid biosynthesis pathway.